These universal programs also benefited higher-income families, who shifted in large numbers from private to public preschool. Higher-income children didn't experience the same impact in later test scores. But in these two states, the education subsidy was substantial for their parents: "A back-of-the-envelope calculation based on our estimates," Cascio and Schanzenbach write, "suggests that this spending reduction amounts to an income transfer of between $3,000 and $5,600 for families that switch out of private programs."

The findings are published in a new National Bureau of Economic Research paper. Cascio and Schanzenbach note that several states already have high-quality preschool programs that serve only a few children, or low-quality programs that serve many children. But Georgia and Oklahoma have state-funded programs that "score high on both counts," making them relatively good models for what this policy might look like elsewhere.

These two state-funded universal programs only date to the 1990s, so it's currently impossible to measure the later life outcomes of children who enrolled (that will take more time). But the results are compelling through grade school. Children of mothers with less education themselves – who have no more than a high school diploma – are significantly less likely to enroll in preschool without a public option. But Cascio and Schanzenbach estimated that the preschool enrollment rates for these children were 19 to 20 percentage points higher in Georgia and Oklahoma than they would have been without these programs.

Mothers from these same families spent less time with their children (likely a function of the fact that they were now in preschool). But they spent more "quality" time on activities like reading, playing, talking and constructing art projects.

It's unsurprising that universal preschool would do more for families who simply wouldn't have this option than for families who would otherwise just pay for private preschool. But Cascio and Schanzenbach hint at a compelling argument for why it might make sense to send all of these children to school together:

On one hand, these findings would appear to suggest that an untargeted national preschool program would result in substantial substitution from private to public preschools, driving up costs and limiting program efficacy. On the other hand, the presence of higher-income children in the universal preschool classrooms in Georgia and Oklahoma—which may help to attract better teachers or have positive spillovers for lower-income children—may be what truly makes these programs “high quality.”

That could be the ultimate benefit of programs aimed at everyone, and not just low-income families with the greatest need.

Top image of President Obama visiting a pre-K classroom in Decatur, Georgia, earlier this year: Jason Reed/Reuters

About the Author

Emily Badger is a former staff writer at CityLab. Her work has previously appeared in Pacific Standard, GOOD, The Christian Science Monitor, and The New York Times. She lives in the Washington, D.C. area.